United States | Chicago

Predictable policing

A hot summer awaits the city’s new police chief

| CHICAGO

IT WAS Eddie Johnson’s first big test. Memorial Day weekend usually marks the start of the most violent period of the year, as the crime rate rises along with the temperature (see chart). Thousands of officers patrolled the city’s parks, beaches and neighbourhoods, including Mr Johnson, the boss of Chicago’s besieged police force since April, who worked a night shift. Fixed-wing aeroplanes circled the area’s expressways, which have recently seen a spike in shootings. In the run-up to the weekend Mr Johnson launched one of the biggest anti-gang raids in Chicago’s history, resulting in the arrest of 140 gang members and the seizure of numerous guns, as well as drugs apparently worth tens of thousands of dollars.

Considering the steep rise in gun violence this year, the sheer size of Chicago’s territory, the complexity of its social problems, the large number of fractious gangs with ever-younger members and the recent breakdown in trust between residents and the Chicago Police Department (CPD), Mr Johnson has taken on perhaps the toughest job in law enforcement in the country. The results of the Memorial Day operations were mixed: killings were down this year, with six murders, including one of a 15-year-old girl, between Friday morning and Tuesday morning, compared with 12 last year. Shootings were higher: 63 compared with 56.

From the start of the year until mid-May, the number of murders increased by 62% to 216. Shootings also rose by 60%. Many theories compete to explain why. One is the low morale of CPD officers, many of whom feel they are unfairly vilified and “are all being grouped with Jason,” says a former cop, referring to Jason Van Dyke, a white police officer who shot a black teenager 16 times as he lay in the road in 2014. A task-force subsequently appointed by the mayor to look at race and policing concluded in April that the CPD has “no regard for the sanctity of life” when it comes to black Chicagoans.

Mr Johnson reckons that the problem is lack of confidence in the justice system. He argues that trust has broken down—between the police and the policed, between the police and an “overburdened and broken” judiciary, as well as between the officers and their leaders. In some ways, though, the CPD has suffered from an excess of trust, among officers at least. On May 31st the city paid out $2m to settle a lawsuit with two police officers who say they were targeted by colleagues and even suffered death threats after they informed on corrupt cops who ran a criminal fief in a housing complex on the South Side.

Daily chart: Revisiting the world's most violent cities

Trust will take time to rebuild, but Mr Johnson hopes that technology will pay dividends sooner. The CPD confiscates 150-200 guns per week on average, more than New York and Los Angeles combined. (Though Chicago and Illinois have strict gun laws, it is easy to buy a gun in Indiana or Wisconsin, a short drive from the city.) The department wants to make more use of the CPD’s “Strategic Subject List” (SSL), which is based on a computer algorithm developed by the Illinois Institute of Technology that calculates the propensity of individuals to get shot or shoot. The fourth iteration of the SSL, the one now in use, has become really good in its murderous predictions, according to Mr Johnson.

The software looks at ten variables, including a person’s previous arrests and convictions, gang affiliations and involvement in shootings. People are ranked according to their probability of becoming a “party to violence” (PVE), either as victim or assailant. According to the CPD, a mere 1,400 people are responsible for most of the gun violence in a city of 2.7m. Of the 140 arrested in the recent gang raid, 117 were already on the SSL. Three-quarters of shooting victims and more than 80% of those arrested for shootings so far this year were also found to be on the list.

The SSL is a work in progress: the police department is constantly updating the list and fine-tuning its technology. It is also trying to use its data to prevent crime. The SSL score ranges from one to 500, with higher scores representing greater risk. Since 2013 officers, social workers and community leaders have visited the homes of more than 1,300 people with high scores; this year the CPD aims to reach 1,500 people likely to be involved in violence and to meet gang members every other week. Mr Johnson’s next big test will be the weekend of the 4th of July. Last year ten people were killed and 55 shot while everyone else was celebrating Independence Day.

This article appeared in the United States section of the print edition under the headline "Predictable policing"

Free speech under attack

From the June 4th 2016 edition

Discover stories from this section and more in the list of contents

Explore the edition

Discover more

Do undocumented immigrants have the right to own guns?

A federal court in Chicago decides that some do. Republicans are outraged

Chicago wants to stop Glock pistols being turned into machineguns

The city is suing the manufacturer


Georgia’s black Republicans have a battle plan for 2024

Joe Biden will have to work harder to win the state’s black voters this year